UsingMac has posted an exhaustive look at iTunes from the perspective of making your working life better. From basic tips like shuffling songs and shuffling movies to more advanced tips like using Terminal to set a half-star rating, it's well thought out.
My favorite tip involves browser mode. Many people (in my experience at least) overlook this feature. I find it to be a killer way to categorize and find just what you're looking for, across genres, years, styles, etc. Of course, I'm that annoying guy who gets all excited over tags, charts and graphs, so keep that in mind.
Check out the article and feel free to share you own.